Not 100% sure I'm understanding your question. But have you bought an OBD2 scanner? That's the first diagnostic tool I go to.
I have two. One is wired the other uses BT to an app. I prefer the BT set ups
This obd2 reader is one of the best rated. It is android only and you need to purchase an app for your device but the price is good. I wonder if they are working on an apple app.